PROJECT SUMMARY Prevention of mother-to-child transmission (PMTCT) efforts have reduced the rates of vertical transmission to 2.7%, however, optimal antiretroviral therapy (ART) adherence remains a difficult goal to reach, particularly postpartum. The contribution of the proposed research is expected to be two-fold: 1) to gain an understanding of how influential contextual, interpersonal, clinic, and individual level factors change during key moments of transition during pregnancy and postpartum and influence ART adherence and 2) to develop bio-behavioral interventions to assist mothers in maintaining their adherence to ART postpartum. Candidate: I am a social psychologist with a background in ART adherence socially disadvantaged groups in the United States. I am applying for a five-year K01 Career Development Award to obtain training, mentorship, and research experience to become an expert in maternal health among women living with HIV in resource limited settings and an independent investigator capable of obtaining R01 funding. Mentoring: I have put together an exceptional mentoring team with extensive experience in HIV treatment and prevention research in South Africa that integrates epidemiology, qualitative methods, and clinical science. Drs. Don Operario and Mark Lurie will serve as co-Primary mentors and bring complementary expertise in international HIV behavioral intervention development and infectious disease epidemiology. In addition to my two Primary mentors, my co- mentors provide expertise in specific content areas and methodologies and are based in both the U.S. and South Africa (ZA). My co-mentorship team includes: Dr. Susan Cu-Uvin (U.S.-based, clinical management of HIV, obstetrics and gynecology), Dr. Landon Myer (ZA-based, perinatal epidemiology, postpartum ART adherence), Dr. Abigail Harrison (U.S.-based, longitudinal qualitative methods, sexual and reproductive health), and Dr. Christopher Colvin (ZA-based, qualitative methods, maternal child health). Training: Specific training in perinatal epidemiology, longitudinal qualitative methods, theory-based interventions, cross-cultural intervention development and evaluation will be achieved through intensive mentored training, coursework, workshops and directed readings and primary ZA research. Guided by my excellent mentorship team, these training and research experiences will establish my independent investigator career as an expert in developing HIV treatment and prevention interventions to address maternal health in high impact, low resource settings, that take into account key moments of transition and change that impact health behaviors. Research: The goals of the proposed project are to (1) identify contextual, interpersonal, clinic, and individual level factors that influence women's HIV treatment adherence during key period of transition during pregnancy and postpartum; (2) evaluate a Transition Theory-based bio-behavioral intervention to improve ART adherence postpartum using a small scale randomized controlled trial; (3) assess participants' experiences of the intervention, perceived usefulness, and identify ways to refine the intervention for future evaluation